Lesson Plan

Connect

Scissor lifts are designed for easy and safe access to elevated positions and are often used where ladders are not an option. A scissor lift’s work platform provides space for tools and movement, and can lift a heavy load.

Build the Scissor Lift and investigate how its function is influenced by weight and height. Let’s find out!

Construct

Build the Scissor Lift
(All of book 1A and book 1B to page 11, step 15).

Have the students reflect on their investigations by asking questions such as:

• What did you predict would happen and why?
• How does the Scissor Lift work? It is a series of first class levers each squeezing the next one. The pivot points are the pegs in the centre of the beams.
• How did you make sure the tests were fair? Did you empty the air tank?

Continue

How much pressure is needed?
You know how many pumps are needed to raise the Scissor Lift to its maximum height. Now add the manometer and find out how much pressure is needed (page 20, step 24).

First, predict how much pressure is needed to raise Scissor Lift A to its maximum height. Record your prediction on the worksheet.

Then, test how much pressure is needed. Record your findings on the worksheet.

Next, follow the same procedure for Scissor Lifts B, C and D. Test several times to make sure your results are consistent.

Optional: Further investigations
Why does the pressure drop immediately after the Scissor Lift has reached its maximum height?When the cylinder piston extends the total area for compressed air has increased.
The pressure adaptation the new total area results in a small pressure drop.

Teacher Support

Students will explore the concepts of:
Area
Behavior of gases under pressure
Forces
Assembling components
Control of mechanisms
Evaluating
Using mechanisms - levers